Pulp-screen.



B. J. POPE & J. W. MULLEN.

PULP SCREEN.

APPLICATION FILED 11011.2, 1911.

1,032,701. Patented July 16, 1912.

. 2 SHEETSSHEET 1.

E. J. POPE & J. W. MULLEN.

PULP SCREEN. APPLICATION FILED NOV.2, 1911.

1,032,701 Patented July 16, 1912. 2 SHEETSSHEET 2.

UNITED STATES PATENT OFFICE.

EDWARD J. POPE, OF HOLYOKE, MASSACHUSETTS, AND JOHN W. MULLEN, ST.

JOSEPH, MICHIGAN.

PULlP-SCREEN.

fl '0. all whom it may concern.

Be it known that we, EDWARD J. Porn and J OHN W. MULLEN, citizens of the United States, residing at Holyoke and St. Joseph, respectively,- in the counties of Hampden and Berrien, respectively, and States-of Massachusetts and Michigan, re spectively, have invented certain new and useful Improvements in Pulp-Screens; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as ;will enable'others skilled in the art to which it appertains to make and use the same;

Our invention relates topulp screens or strainers used in paper making. In all fiat screens for this purpose, it has been necessary to either knock or vibrate the screen itself or the bottom of the vat under the screen, or tocreate a suction to draw the pulp through said screen. Heretofore, the suction has been created by the use' of a rubber diaphragm placed under the screen and vibrated rapidly to a limited extent.v The known vibrating screens are operated by shaking said screens laterally or up and down by means of cams, cranks or knockers.-

One object of our present invention is to secure the desired result in a much more positive and effective manner with an expenditure of much less power and in a ma- I chine which will not require constant repairs and attention.

All screens of this kind must be kept clean inorder to have the work done properly. Considerable trouble has been experienced in devising inexpensive and practical means for removing the coarse pulp and dirt which clings to "the surface of the screen plates, preventing the free passage of the finer pulp. Heretofore the plates have been generally cleaned by scraping the surface thereof and taking the coarse pulp out by hand. Ihis method, however, has been found to be undesirable for the reason that some of the coarse pulp and dirt is forced through the screen plates during the scraping, there: by impairing the quality of the screened p lp- Another object of the invention is to clean the screen plates without injuring or lowering the quality of" the output of pulp.

With these ends in view, our invention consists broadly of an oscillating box arranged above the screen plates and adapted Specification of Letters Patent.

Application filed. November.2, 1911.

Patented July 16, 1912. Serial No. 658,076.

to feed the pulp over the entire surface of said plates, first washing one way and then the opposite way, causing all particles of pulp and dirt which may cling to the screen plates to be washed into troughs at the sides of the screen. The pulpand dirt which collects in said troughs may be carried to an auxiliary screen for further treatment. All of the pulp which passes through said auxlhary screen may be returned to the main screen, preferably by the same pump that delivers it in the first place.

The invention also consists of an improved suction creating mechanism which alternately draws the pulp through the screen and forces the refined material from the vat into the discharging trough.

The invention consists further in the fea-' tures of construction and combinations of parts hereinafter described, illustrated in the accompanying,drawings, and specified in the appended claims. In the accompanying drawings: Figure 1 1s a plan view of a screen constructed in accordance with our invention. Fig. 2 is a' central longitudinal vertical sectional view of the same, and Fig. 3 is a transverse vertical section taken in line with one of the passages leading from the vat to the discharg ing trough.

It will be understood that the auxiliary screen, above referred to as designed for refining the coarser pulp which is washed into the lateral troughs of the primary screen may be-of the same design as said primary screen or of any other known construction. It, therefore, suffices to illustrate the primary screen in the accompanying drawings:

Referring more particularly to the drawings, 1 designates the body or vat which mounted on suitable supports 2 and contains the screen plates. 3. The oscillating feed trough 4 is mounted at 5 above the body 1 of the screen and extends longitudinally thereof. Said feed trough is adapted to be actuated by an arm 6 to which power may be applied from any suitable source for imparting a rocking motion thereto.- Troughs 7 extend longitudinally at the sides of the feeding trough, being separated from the main portion thereof by tiangesor rims S. Openings 9 are formed in the bottom of said troughs 7 leading to spouts 10 which extend down near tothe screen plates and have verse partition 15.

their extremities turned slightly inward, as at 11, whereby the pulp is discharged toward the center ofsaid screen plates. The

lower or'delivery ends of said spouts are preferably contracted intolong narrow discharge openings 11 which extendlongito distribute the pulp evenly over the sur, .faces of the screen plates.

The function of the flanges or runs 8 in the feed trough is to give the pulp more force when said trough is tipped or rocked. The higher these strips are made, the more sudden and forcible will be the flow of pulp into the spouts 10 thereby increasing the force of the delivery of the pulp onto the screen plates. The vat contains two lateral troughs 12 arranged at either edge of the screen plates to receive the coarse and dirty pulp which is washedoif of said screen plates by the oscillation of' the feed trough. The ends 13 of said troughs 12, are adapted to connect with the auxiliary screen already referred to but not illustrated. The space below the screen plates can be in one or more chambers, two being illustrated at 14,

by way of example, separated b a trans- Openings 16 in the bot toms of said chambers lead to an extending cylinder 17 in which a piston 18 is mounted." The piston rod 19 extends through one end of the cylinder where it is suitably packed, as at 20, and is connected by a pitman21 to the-crank 22 of an actuating shaft 23 also carrying a drive pulley 24 by means of which said piston may be reciprocated. Directly below each of the passages 16 lead- 7 ing, from the chambers 14 to the cylinder 17, there are pockets 25 .for catching all; heavy material and grit which may pass through the screen plates. A discharge box 26 is located at one side of the screen and communicates with the chambers 14 via passages 27. The outer openings of said passages are covered by flap valves 28 preferably pivoted at their upper edges and normally arranged slightly inclined outwardly from the vertical when seated. The screened pulp is carried off from the box 26 via a discharge opening. 29 therein, illustrated in Fig. 1. I

The operation of'the screen is as follows: The pulp is delivered into the rocking feed trough 4 which in-turn discharges it onto the screen plates 3 through the spouts 10.

The coarser part of the pulp which is discharged upon the screen plates is washed therefrom, with the dirt, etc., which would otherwise tend to stop up or close the perforations in said screen plates, by the oscillating motion of the spouts. This matter is carried ofl'by the troughs 11 at the sides of the screen plates for subsequent treatment, as hereinbefore explained. The reciprocation of the piston 18, in itscylinder 17, alternately creates a suction in each of the chambers 14 belowthe screen plates, said suction being increased by the automatic closing of the valves 28, and forces the pulp which has been screened from said chamber through its passage 27 into thedischarge box 26'at which time the valve 28 is automatically opened. By placing the valves and valve seats on the slight incline illustrated, the weight of the screened pulp standing in the box 26 is utilized as an "auxiliary means of holding each valve shut dur ing the stroke of the piston which creates a suction in its chamber 14.

It will be noted that the construction illustrated employs a single piston for operating 't-wo chanibers, the stroke of said piston which creates a suction in one chamber si- 'multaneously forcing the pulp from the other chamber, and vice versa. VVe do not confine ourselves to this particular form of cylinder, however, as various changes may be made in its construction and position without departing from the spirit or sacrificing the advantages of our invention.

We claim:

1. The combination, with a screen plate and a trough at its edge, of means extending down near to said plate for deliveringpulp thereon, the discharge opening of said delivery means being inclined toward said trough, and means to oscillate said delivery means whereby the coarser pulp and dirt.

are washed from said screen plate into said trough by the operation of delivering the pulp to the screen plate. 1 I y i 2. The combination, with a screen plate and troughs at its lateral edges, of means extending down near to said plate adjacent to each of its lateral edges for-delivering pulp thereon, the discharge opening in each of said delivery means being inclined away from the trough'adjacent thereto, and means to oscillate said delivery means whereby the coarser pulp and dirt are washed from said screen plate into said trough by the operation of delivering the pulp to the screen plate. p

3. The combination, with a screen plate, anda trough at its edge, of a feed trough arranged above said plate, a delivery spout leading from said feed trough and extending down near to the surface of said screen screen plate, and means to oscillate said spout for the purposes specified.

4. The combination, witha screen plate, and a: trough at its edge, of a feed trough arranged above said screen plate, a delivery spout secured rigidly to said feed'trough and extending down near to the surface or" the screen plate for delivering pulp thereon, the lower end of said spout being inclined toward the trough at the edge of the screen plate, and means to oscillate said feed trough for the purposes specified.

5. The combination, with a screen plate, and a trough at its edge, of a spout extending down near to the surface of said screen plate for delivering said pulp thereon, the lower end of said spout being inclined away from the trough at the edge of the screen plate and contracted laterally to form a narrow longitudinal discharge opening, and means to oscillate said spout, all for the purposes specified.

6. The combination, with a screen plate and troughs at its edges, of a feed trough arranged above said screen plate, spouts leading from said feed trough down near to-the surface of said screen plate adjacent to its lateral edges for delivering pulp on said plate, the lower end of each spout being inclined away from the trough at the edge of the screen plate adjacent thereto, and means for oscillating said spouts in unison for the purposes specified.

7. The combination, with a screen plate, and troughs at its edges, of a feed trough arranged above said screen plate, spouts leading from said feed trough down near to the surface of said screen plate adjacent to its lateral edges for delivering pulp on said plate, the lower end of each spout being inclined away from the-trough at the edge of the screen plate adjacent thereto and contracted laterally to form a narrow longitudinal discharge opening, and means to oscillate said spouts in unison, all for the purposes specified.

8. The combination, with a screen plate, oi a teed trough arranged above the same,

longitudinal flanges in said feed trough forming channels at opposite edges thereof, spouts rigidly secured to said feed trough and adapted to deliver pulp from the channels therein on to the screen plate, and means tooscillate said feed trough for the purpose specified.

9. The combination, with. a vat, of a screen plate therein, said vat having a chamber below said screen plate and a discharge passage leading from said chamber, a cylinder communicating with said chamber, a piston mounted in said cylinder, means to reciprocate said piston whereby a suction is created in said chamber during the movement of said piston in one direction and the pulp is discharged from said chamber through its delivery passage during the movement of said piston in the opposite di-- rection, and a valve in said discharge passage adapted to automatically close the same during the exhaust stroke of the piston.

' 10. The combination, with a vat, of a screen plate therein, said vat having two chambers arranged below. said screen 'plates and discharge passages leading from each of said chambers, a cylinder communicating with both chambers, and a piston mounted to reciprocate in said cylinderbetween the passages leading therefrom to said chambers whereby the movement of the piston in one direction will simultaneously create a suction in one chamber and discharge the'pulp from the other chamber and vice versa on the return stroke, and valves in the discharge passages troin said chambers, each valve adapted to automatically close its passage during the movement of the piston which creates a suction in its chamber.

In testimony whereof, we each afiix our signatures, in presence of two witnesses.

EDWARD J. POPE. JOHN W. MULLEN.

Witnesses for Edward Pope:

H. C. SMITH, G. P. MARnANn.

Witnesses for John W. Mullen:

GEO. H. MARSHALL,

WILLARD J. BANYON. 

